Confused by some lines of a sticom
I'm watching a old sitcom called The Golden Girls. There's some lines I can't understand.
Blanche is looking for a new roommate and she interviewed a woman called Madame Zelda. When her name was spoke by Blanche there's so much laughter. I'm curious about who is Madame Zelda? It sounds like that she is a famous Psychic, but I can‘t find her information in Wiki.
And Madame Zelda said:“Mrs. Devereaux, you must leave this house at once. It's possessed by an evil spirit.”
Blanche said:“Actually, it's possessed by Miami Federal. And at seven percent, you couldn't blast me out of here.”
I don't know what the “ at seven percent” means.
When Dorothy met Rose, Rose was saying:"Oh, it's been such a lovely day. Mr. Sunshine really gave us one of his biggest and brightest smiles. Oh, I feel like putting my arms around Mother Nature and giving her a big kiss. Hi, you must be Dorothy."
Dorothy:"And you must be Mrs. Rogers."
I know Mrs. Rogers is a kind of spices, but why Dorothy call Rose that?